An absolute coordinate formulation for three-dimensional flexible pipe analysis

A rather general absolute coordinate formulation is presented for the analysis of flexible pipe structure. The present formulation uses a similar line of approach adopted by Paulling and Webster (1986), which avoids the need of having to use infinitestiminal or finite rotations as nodal variables at the local floating frames of reference by expressing the structural response characteristics in terms of globally based position coordinate and its derivative to allow an accurate non-linear description of the pipe kinematics to be made, and extend the idea to include bending–torsion coupling, axial–radial coupling and bend restriction effect. The present formulation is also capable of handling internal flow effect, pre-bent section and irregular seabed interaction with friction effect, thus allowing an alternative general tool to be developed for riser, pipeline and flexible hose analyses.